Alfred walter stokes



(No Model.)

A. STOKES. APPARATUS FOR DETERMINING FAT IN MILK. No. 602,780. PatentedApr. 19, 1898.

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UNITED STATES PATENT Orricn.

ALFRED IVALTER STOKES, OF LONDON, ENGLAND, ASSIGNOR TO THE R. A. LISTER8: COMPANY, LIMITED, OF DURSLEY, ENGLAND.

APPARATUS FOR DETERMINING FAT IN MILK.

SPECIFICATION forming part of Letters Patent No. 602,780, dated April19, 1898.

Application filed October 27, 1897. Serial No. 656,567. (No model.)Patented in England June 24, 1895, No. 12,184.

To all whom it may concern.-

Be it known that I, ALFRED WALTER STOKES, F. O. S., F. I. 0., a subjectof the Queen of Great Britain and Ireland, and a resident of London,England, have invented a certain new and useful Apparatus forDetermining Volumetrically the Amount of Eat in Milk or other Matter,(for which I have obtained a patent in Great Britain, No. 12,184,bearing date June 24, 1895,) of which the following is a specification.

By means of this apparatus the amount of fat in milk or other matter canbe volumetrically determined in a ready manner and without the aid ofany special measuring appliance, and it can also after use be readilyand thoroughly emptied and cleaned.

Figure 1 is a longitudinal section of the apparatus; Fig. 2, a sectionthrough a cap for closing one end, and Fig. 3 an elevation of a stopperfor closing the other end.

The apparatus consists of a glass tube open at both ends for thoroughcleaning and formed near one end with a much narrower part 5, which ismarked off with gage indications or calibrated to show in percentagesand in tenths of a per cent. the fat in the milk or other matter. In theother part the tube is expanded or bulb-shaped in two placesviz., at 3and at 4so that it may there contain a larger quantity of the liquids tobe used than the rest of the tube. One end of the tube can be closed byan indiarubber or other stopper 1, and the other end by a screwed cap 7,with india-rubber pad within. The screw-thread 6 may be formed on theglass tube or on a metal or other collar fixed thereon. Instead of thescrew I may use a bayonet-joint. The tube is marked in three places-via,at 8, 9, and 10-so that the exact quantities of the liquids may bepoured in by hand without the use of a special measuring vessel, thussaving much time and trouble.

The method of using the apparatus when applied to the testing of fat inmilk is as follows: The screw-cap 7 is screwed on tightly. Then someamylic alcohol is poured in at the mouth 2, with that end up, till itreaches in the tube up to the mark 8. This measures, say, one an done-half cubic centimeters. Next sulfuric acid of a specific gravity offrom 1.820 to 1.830 is poured into the tube up to the mark 9. Thismeasures thirteen and onehalf cubic centimeters of sulfuric acid. Themilk or other liquid is then poured in up to the mark 10. This measuresfifteen cubic centimeters of the milk. The stopper 1 is then tightlyfitted into the mouth 2, so that a space of about one cubic centimeteris left between it and the milk, and the whole apparatus is well shakenfor about a minute till the fluids are Well mixed, the screw-cap beingmeanwhile slightly eased to allow for escape of surplus gas. Theapparatus should now at once be rotated in any suitable centrifugalmachine at five hundred revolutions or more per minute. If it be sorotated, the calibrated end 5 6 being placed nearest to the center ofrotation, it will be found at the end of about five minutes that the fathas separated out as an oily column in the calibrated part 5. Itspercentage may readily be ascertained by counting the divisions of thepart 5 thatit occupies, each of which divisions represents one-tenth ofone per cent.,by weight, of fat. The screw-cap 7 may either be taken offor be left on during the rotation, and the reading of the percentage offat is made with the screw-cap end uppermost, as in Fig. 1.

In default of a centrifugal apparatus the tube should after mixing beimmersed with its contents into water at a temperature of to 82centigrade, the screw-cap end being vertically uppermost. If kept atthis temperature for at least an hour, the fat will rise into thecalibrated part 5 of the apparatus and can there be read off.

After each testing operation the tube should be emptied and cleaned out,which can be easily and thoroughly effected by removing the stopper 1and the screw-cap 7 and then washing out with hot water.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is

1. Apparatus for determining volumetrically the proportion of fat inmilk, consistin g of an open-ended straight glass tube having in theorder named a terminal chamber, a contracted graduated length, a secondchamber, a contracted portion, a third chamher and a contracted portion,said second and third chambers each of greater capacity than the first,in combination with means for clos ing the open ends of the tube,substantially as set forth.

2. Apparatus for determining volumetrically the proportion of fat inmilk, consisting of an open-ended straight glass tube having in theorder named a terminal chamber, a contracted graduated length, a secondchamber, a contracted graduated portion of greater diameter than thefirst graduated portion, and a third chamber terminating in a contractedgraduated portion, said third chamber of greater capacity than the firstor I 5 second and said second chamber of greater capacity than saidfirst, in combination with means for closing the open ends of the tube,substantially as and for the purpose set forth.

ALFRED WALTER STOKES.

Witnesses:

V. JENSEN, FREDK. HARRIS.

